phidgets_c_api: deleted package (will be downloaded as external project in phidgets_api)
phidgets_drivers: removed phidgets_c_api dependency
phidgets_api: removed phidgets_c_api dependency
phidgets_api: added libphidget header file to package
phidgets_api: updated path to libphidget header file
phidgets_api: added libphidget21 dependency as cmake external project
phidgets_api: added script to setup udev rules for Phidgets devices
phidgets_drivers: updated README.md